Let's say you're a scientist, and you've invented what you think is a useful treatment for pain. But you have a problem. You don't have the money to go through the regulatory approval process. Should you try to sell it to consumers anyway, and run the risk of being accused of selling snake-oil?

That's the dilemma Ted Price and his colleagues faced. Price is a researcher at the University of Texas, Dallas. His work focuses on solving a vexing question about pain: why does pain persist even after injuries heal?